Calutron



Aug. 12, 1958 F. H. SCHMIDT CALUTRON INVENTOR. r7950 H SCH/W0 r.

2 Sheets-Sheet 1 Filed Feb. 4, 1946 UnitedStates Patent,

2,847,577 CALUTRON Fred H. Schmidt, Berkeley, Calif., assignor to the United States of America as represented by the Atomic Energy Commission Application February 4, 1946, Serial No. 645,460 4 claims. or. 250-413 which the present invention is most readily incorporated.

In a device of the type referred to, it is customary to provide an electrical arc operating upon a transevrsely flowing gas :stream in order/to ionize some of theparticles within the gas stream. It is considered that the nature, shape, and functioning of the are are all considerably dependent upon the nature of the gas passage provided for ionization, upon the contour of the electrical fields in the vicinity of the arc, and upon the contour of the metal parts in theenvironment of the arc. Additionally, in a calutron the ions move in a magnetic field and a stream of ions is withdrawn from one side of a columnar arc. It is deemed important to accurately define the projected area of the arc from whence the ions are withdrawn.

It is, therefore, an object of my invention to provide means accurately definining the terminus of the gas discharge passage from a source block in a calutron.

Another object of my invention is to provide means that can be set or adjusted accurately to define the projected area of the are from whence ions are withdrawn.

An additional object of my invention is to provide means that can be preset, adjusted, or even replaced, if desired, for the purpose of varying the location or terminal contour of the ion efiiux pasasge in a calutron ion source.

An. additional object of my invention is to provide means for feasibly locating defining plates of special material in the vicinity of an arc to reduce erosion and deterioration.

The foregoing objects are attained in the embodiment of the invention described hereinafter and illustrated in the accompanying drawings, in which:

Figure l is a fragmentary view of a calutron mechanism, there being shown in section a calutron tank having situated therein a calutron source unit, portions being shown in side elevation and portions being broken away to disclose the interior construction of the mechanism;

Fig. 2 is an exploded, isometric view of the charge chamber and its immediate environment, some portions being disclosed in cross section to illustrate clearly the interior arrangement of the calutron ionization or source mechanism; and

Fig. 3 is a cross section through the source block illustrated in Fig. 2, the plane of section being indicated by the line 3-3 of Fig. 2.

Although a calutron is described in great detail in the above-identified patent of Ernest 0. Lawrence, it is briefly summarized herein. A calutron is inclusive of an ion source unit, generally designated 6, disposed in the evacuated interior 7 of a tank defined by a side wall 8, a top wall 9, and a bottom wall 11. The tank is situated in a "ice magnetic field established between an upper pole piece 12 and a lower pole piece 13 of an electromagnet.

The source block 6 is electrically insulated from the tank wall 8 and is supported at the end of a mounting stem 14, extending through an aperture 16 in the wall 8 of the tank and carried by a mounting and adjusting mechanism 17. This latter mechanism forms no part of the present invention, and is therefore not described herein in detail. The mechanism 17 is in turn supported on a framework 18 fastened to an electrical insulator 19, itself secured to the tank wall 8 by an appropriate fastening mechanism 21.

As more particularly disclosed in Fig. 2, theinner end of the stem 14 is connected to the source block 6 by a thermal insulator 23, as the block 6 itself is preferably fabricated of a thermally conducting material such as a metal, for example copper. Within the block 6 is disposed an electrical heating coil 24, supplied with energy by alead 26 passing through the insulator 19 to an exterior source of energy. Adjacent the heater 24, in thermally conducting relationship therewith, is a gas distribution chamber 27, constituted by a cavity within the block ,6 and having anoutlet passage 28 to the interior of the tank 7.

Closing theupper end of the heater cavity 24 and the upper end of the gas distribution cavity 27 is a cover plate 29, secured by fastenings 31 and forming a support for a pair of filament leads 32 and 33 extending through the insulator 19 to a source of energy and terminating in grips 34 and 36 holding a filament 37 over an aperture 38 in the plate 29 and in registry with the passage 28. A securing block 41 holds the filament leads 32 and 33 in position, while the enclosure of the filament is completed by a cap plate 42, removably positioned by fasteners (not shown) operating through the cap plate apertures 43.

For supplying the gas distribution chamber 27 with a vapor or gas to be subsequently ionized, the block 6 is provided with a pair of cavities 46 and 47, each of cylindrical form and extending almost but not quite entirely through the metal of the block, so that heat from the source 24 is conducted to the walls of each of the cavities 46 and 47. The cavities communicate with the chamber 27 through outlet apertures 48 and 49, respectively, so that gas flow from both chambers 46 and 47 to chamber 27 is readily effected. The two chambers 46 and 47 are simultaneously closed by a cover plate 51, preferably held removably in position on the block 6 by fastenings (not shown) operating through apertures, such as 52, in the top plate 51 and in the block 6.

In particular accordance with the present invention, the passageway 28 leading from the oblate gas distribution chamber 27 does not extend in itself to the exterior face 61 of the source block 6. Rather, the source block over an appropriate area of the face 61 is countersunk or is provided with a recessed portion 62, intersecting the passage 28 and defining a planar surface. In good thermal and electrical contact with the block 6 and disposed against the surface 62 is a pair of arc slit plates 63 and 64, respectively. Each of the plates is preferably like the other in general, and is conveniently fabricated of a metal especially resistant to erosion by the arc.

Each of the plates is designed to be coplanar with the other and to be adjustable or movable transversely of the axis of the passage 28, so that the plates 63 and 64 can be approached quite closely to each other or can be held in relatively or mutually remote locations. This is preferably effectuated by providing each of the plates 63 and 64 with an elongated slot 67, especially as shown in Figure 3, through which extends a fastener 68, such as a screw, engaging appropriate threads within the source block 6. By virtue of this construction, either one or 3 both of the plates 63 and 64can be preset or adjusted or removed and replaced, as desired.

Appropriately to establish the terminal contour of the gas effiux passage 28 and accurately to define the projected area of the arc from-whence ions are Withdrawn, the facing edges-69 and 71 of the arcslit plates are appropriately contoured. In the present instance, they are beveled. The contour ofthese-platesnot only establishes the boundary of the gas flow channel, but also establishes the contour of the immediately adjacent electrical field, since the plates 63 and 64 are both conductors, and being in contact With the "conductin'gblock 6 are necessarily at the same electrical potential as 'the source block.

In accordance 'with the invention, therefore, there is provided a means for accurately presetting the size and location of the gas and ion efilux opening from a calutron source, for determining as desired the contour of the electrical field in the vicinity of the arc, and for generally improving the operation of 'the calutron source unit.

What is claimed is:

1.'A calutron comprising an electrically conductive block having a gas ionizing chamber therein and a passage establishing communicationbetween said chamber and the exterior of said block, and a pair of electrically conductive coplanar plates mounted upon said block for individual movement transversely of said passage, means establishing an electrical potential upon said block and said plates, and means engaging said block and said plates for holding said plates in selected transverse position thereby to assist in establishing the contour of the electrical field adjacent said block.

2. Apparatus as defined in claim 1 wherein the complementary facing edges of said plates provide a dihedral angle of passage for the ionized material.

3. A calutron comprising an electrically conductive block having a gas ionizing chamber therein and a passage establishing communication between said chamber and the exterior of said block, an electrically'conductive plate mounted upon said block for movement transversely-of said passage to define the terminus of said passage, means establishing an electrical potential upon said block and said plate, and means engaging said block and said plate for holding said plate in a selected transverse position thereby to assist in establishing the contour of the electrical field adjacent said block.

4. Apparatus as defined in claim 3 wherein saidzplate is mounted-within a recessed portion'of said blocktthereby to provide a substantially flush outer surface of said block and said plate.

References Cited in the file of this patent UNITED STATES PATENTS -Washburn June 26, 1945 Washburn Oct. 2, 1948 

